1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method for executing copying and transmission processing by using a scanner, and a computer program.
2. Description of the Related Art
There is a technology; so called “super-resolution” for improving resolution using a plurality of images each having a certain level of resolution. The use of the technology enables conversion, for example, from an image of 600 dpi to an image corresponding to 1200 dpi, thus enabling to achieve a high resolution image by using a device which is the same as that used before.
In order to carry out a super-resolution technology, a plurality of images each having a phase differing in a sub-pixel order (unit that is smaller than one pixel) are required. Thus, the technology is widely applied to a field such as processing of moving images.
However, the need of a plurality of images for one pixel necessarily consumes more amount of a memory, thus inevitably increasing the size of the memory and the amount of calculation.
Therefore, conventionally, the reduction of the calculation amount and the consumption amount of a memory have been achieved by specifying attention areas from a low resolution input image and increasing/decreasing the number of sheets of images to be synthesized based on the sizes of the areas (for example, refer to Japanese Patent Laid-Open No. 2006-092450).
Moreover, the reduction of the calculation amount and the consumption amount of a memory have been achieved by dividing an input image into important areas and non-important areas and by reducing the number of sheets of images to be used for the non-important areas than that for the important areas (for example, refer to Japanese Patent Laid-Open No. 2005-354124).
In the above-mentioned prior-art technologies for achieving the reduction of the calculation amount and the consumption amount of a memory, the number of input images that are used for the super-resolution processing has been determined by defining important areas by a user or by automatically determining the important areas from parts having the same luminance among a plurality of images.
Although such technologies can reduce the consumption amount of a memory used for super-resolution processing itself, if any image processing is required to be carried out with respect to the super-resolution image after subjected to super-resolution processing, another countermeasure becomes necessary.
Here, the case where printing of a super-resolution image of 1200 dpi obtained by subjecting an input image of 600 dpi to super-resolution processing is performed, will be exemplified.
Conventionally, an image obtained by further carrying out super-resolution processing with respect to a super-resolution image of 1200 dpi has been output as an image suitable for an engine for printing. Here, when image processing is configured with hardware logic, logic corresponding to 1200 dpi is prepared. On the contrary, if more sheets of image data can be prepared for the super-resolution processing, an image having resolution higher than 1200 dpi (for example, 2400 dpi) can also be formed. As the hardware logic when such an image of 2400 dpi is output, logic corresponding to 2400 dpi has to be prepared.
That is, if an image subjected to super-resolution processing is required to be printed, image processing hardware logic corresponding to the output resolution of the image after super-resolution processing should be prepared. This leads to the increase of the circuit scale and the cost. As the countermeasure of this, first, a method can be considered, in which image processing is carried out with respect to a low resolution read image before super-resolution processing, and super-resolution processing is carried out with respect to the image after image processing.
However, in this case, since the number of times of image processing is the same as that of reading of a document, the degradation of the performance occurs. Although, this can be coped with by using a configuration in which a plurality of circuits are made so as to carry out processing in parallel, finally, leading to the increase of the circuit scale and the cost.
As the next countermeasure, a method can be considered, in which image processing is carried out with respect to only one reading image and the resultant image is reflected to super-resolution image data by subjecting it to processing such as resolution conversion processing. However, in this case there arises a problem in that the quality of the output image can not be ensured.
Moreover, conventionally, in the case where multiple readings of a document are carried out in order to generate an output image, the image processing with respect to the super-resolution image has been started after waiting for the completion of all of the multiple readings necessary for giving target resolution to the image after super-resolution processing.
However, in the case where the resolution for carrying out image processing is different from that for an output (for example, the case where the output resolution is higher than the former, an image having resolution sufficient for image processing can be obtained even if all the multiple reading processing has not completed. As described above, even if reading of sheets of image data that are necessary and sufficient for super-resolution processing to the resolution for image processing has already been completed, the super-resolution processing has not started until all of the multiple reading processing have been completed. As a result, many times are required by the time the subsequent image processing has been completed.